The electric energy store of electric vehicles can nowadays be recharged at charging points provided for this purpose. To this end, the vehicle user connects his vehicle to the charging point via a charging cable and initializes the charging operation in a suitable manner, for example by means of authentication using a code at the charging point. During the course of the charging operation, information relating to the charging operation is transmitted via one or more communication channels between the vehicle and the charging point.
It is known in the context of the charging of an electric vehicle with alternating current, to use a charging cable with a terminal, via the connecting elements of which, in addition to the supply of alternating current, so-called PLC communication (PLC=power line communication) is implemented by means of the conductors connected to the connecting elements in the charging cable. PLC communication is known and facilitates data transmission via conductors provided per se to conduct current and voltage (for example 230 volt mains voltage). At the same time, the data signal in the radio-frequency range is modulated to the power supply.
PLC communication performed via the charging-current carrying conductors during alternating-current charging of an electric vehicle has several drawbacks. In particular, the use of charging-current-carrying conductors results in strong electromagnetic emission or to the injection of external electromagnetic radiation since, as a rule, there is no electromagnetic screening for such conductors. This results in an association problem in that it cannot be safely assumed for either the vehicle or the charging point that the signals transmitted via PLC communication originate from a remote station connected to one end of the charging cable. In particular, the electromagnetic emission or injection also enables signals to be received from an adjacent cable. Another problem is that of bandwidth reduction because the signals injected in the conductor reduce the bandwidth available for communication with the remote station. It is also possible that a regulatory problem could occur since, due to the strong electromagnetic emission from PLC communication, in some circumstances, this type of communication within the scope of charging an electric vehicle is not permitted to be used in certain countries.